# CTRDG_IsNumberID

## C Specification

      #include <nitro/ctrdg.h>

      BOOL CTRDG_IsNumberID( u8 numberID );

## Description

Checks whether or not the peripheral corresponding to the Number ID actually exists in the Game Pak

A bit ID and a number ID are assigned to every peripheral built into the Game Pak. The bit ID is `0` when a peripheral is present, and `1` when it is not. More than one peripheral can be built into the Game Pak, in which case multiple IDs are also stored. If there is an ID stored in the AGB Game Pak, it is possible to identify the peripheral.

This function is normally used by the peripheral library to implement functions and to check whether peripherals are present. You should have your application call this function via the peripheral library. Calling this function directly is not recommended.

## Caution

## Arguments

`numberID` | The Number ID

## Return Values

Returns TRUE if the peripheral corresponding to the Number ID exists in the Game Pak.
FALSE if otherwise.

The function always returns FALSE when the check is made after the Game Pak has been removed.

## See Also

`CTRDG_Init`, `CTRDG_IsBitID`, `CTRDG_IsOptionCartridge`, `CTRDG_IsAgbCartridge`, `CTRDG_IsExisting`

## Revision History

10/19/2004 Initial version